1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * udbg for NS16550 compatible serial ports
4 *
5 * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
6 */
7 #include <linux/types.h>
8 #include <asm/udbg.h>
9 #include <asm/io.h>
10 #include <asm/early_ioremap.h>
11
12 extern u8 real_readb(volatile u8 __iomem *addr);
13 extern void real_writeb(u8 data, volatile u8 __iomem *addr);
14 extern u8 real_205_readb(volatile u8 __iomem *addr);
15 extern void real_205_writeb(u8 data, volatile u8 __iomem *addr);
16
17 #define UART_RBR 0
18 #define UART_IER 1
19 #define UART_FCR 2
20 #define UART_LCR 3
21 #define UART_MCR 4
22 #define UART_LSR 5
23 #define UART_MSR 6
24 #define UART_SCR 7
25 #define UART_THR UART_RBR
26 #define UART_IIR UART_FCR
27 #define UART_DLL UART_RBR
28 #define UART_DLM UART_IER
29 #define UART_DLAB UART_LCR
30
31 #define LSR_DR 0x01 /* Data ready */
32 #define LSR_OE 0x02 /* Overrun */
33 #define LSR_PE 0x04 /* Parity error */
34 #define LSR_FE 0x08 /* Framing error */
35 #define LSR_BI 0x10 /* Break */
36 #define LSR_THRE 0x20 /* Xmit holding register empty */
37 #define LSR_TEMT 0x40 /* Xmitter empty */
38 #define LSR_ERR 0x80 /* Error */
39
40 #define LCR_DLAB 0x80
41
42 static u8 (*udbg_uart_in)(unsigned int reg);
43 static void (*udbg_uart_out)(unsigned int reg, u8 data);
44
45 static void udbg_uart_flush(void)
46 {
47 if (!udbg_uart_in)
48 return;
49
50 /* wait for idle */
51 while ((udbg_uart_in(UART_LSR) & LSR_THRE) == 0)
52 cpu_relax();
53 }
54
55 static void udbg_uart_putc(char c)
56 {
57 if (!udbg_uart_out)
58 return;
59
60 if (c == '\n')
61 udbg_uart_putc('\r');
62 udbg_uart_flush();
63 udbg_uart_out(UART_THR, c);
64 }
65
66 static int udbg_uart_getc_poll(void)
67 {
68 if (!udbg_uart_in)
69 return -1;
70
71 if (!(udbg_uart_in(UART_LSR) & LSR_DR))
72 return udbg_uart_in(UART_RBR);
73
74 return -1;
75 }
76
77 static int udbg_uart_getc(void)
78 {
79 if (!udbg_uart_in)
80 return -1;
81 /* wait for char */
82 while (!(udbg_uart_in(UART_LSR) & LSR_DR))
83 cpu_relax();
84 return udbg_uart_in(UART_RBR);
85 }
86
87 static void __init udbg_use_uart(void)
88 {
89 udbg_putc = udbg_uart_putc;
90 udbg_flush = udbg_uart_flush;
91 udbg_getc = udbg_uart_getc;
92 udbg_getc_poll = udbg_uart_getc_poll;
93 }
94
95 void __init udbg_uart_setup(unsigned int speed, unsigned int clock)
96 {
97 unsigned int dll, base_bauds;
98
99 if (!udbg_uart_out)
100 return;
101
102 if (clock == 0)
103 clock = 1843200;
104 if (speed == 0)
105 speed = 9600;
106
107 base_bauds = clock / 16;
108 dll = base_bauds / speed;
109
110 udbg_uart_out(UART_LCR, 0x00);
111 udbg_uart_out(UART_IER, 0xff);
112 udbg_uart_out(UART_IER, 0x00);
113 udbg_uart_out(UART_LCR, LCR_DLAB);
114 udbg_uart_out(UART_DLL, dll & 0xff);
115 udbg_uart_out(UART_DLM, dll >> 8);
116 /* 8 data, 1 stop, no parity */
117 udbg_uart_out(UART_LCR, 0x3);
118 /* RTS/DTR */
119 udbg_uart_out(UART_MCR, 0x3);
120 /* Clear & enable FIFOs */
121 udbg_uart_out(UART_FCR, 0x7);
122 }
123
124 unsigned int __init udbg_probe_uart_speed(unsigned int clock)
125 {
126 unsigned int dll, dlm, divisor, prescaler, speed;
127 u8 old_lcr;
128
129 old_lcr = udbg_uart_in(UART_LCR);
130
131 /* select divisor latch registers. */
132 udbg_uart_out(UART_LCR, old_lcr | LCR_DLAB);
133
134 /* now, read the divisor */
135 dll = udbg_uart_in(UART_DLL);
136 dlm = udbg_uart_in(UART_DLM);
137 divisor = dlm << 8 | dll;
138
139 /* check prescaling */
140 if (udbg_uart_in(UART_MCR) & 0x80)
141 prescaler = 4;
142 else
143 prescaler = 1;
144
145 /* restore the LCR */
146 udbg_uart_out(UART_LCR, old_lcr);
147
148 /* calculate speed */
149 speed = (clock / prescaler) / (divisor * 16);
150
151 /* sanity check */
152 if (speed > (clock / 16))
153 speed = 9600;
154
155 return speed;
156 }
157
158 static union {
159 unsigned char __iomem *mmio_base;
160 unsigned long pio_base;
161 } udbg_uart;
162
163 static unsigned int udbg_uart_stride = 1;
164
165 static u8 udbg_uart_in_pio(unsigned int reg)
166 {
167 return inb(udbg_uart.pio_base + (reg * udbg_uart_stride));
168 }
169
170 static void udbg_uart_out_pio(unsigned int reg, u8 data)
171 {
172 outb(data, udbg_uart.pio_base + (reg * udbg_uart_stride));
173 }
174
175 void __init udbg_uart_init_pio(unsigned long port, unsigned int stride)
176 {
177 if (!port)
178 return;
179 udbg_uart.pio_base = port;
180 udbg_uart_stride = stride;
181 udbg_uart_in = udbg_uart_in_pio;
182 udbg_uart_out = udbg_uart_out_pio;
183 udbg_use_uart();
184 }
185
186 static u8 udbg_uart_in_mmio(unsigned int reg)
187 {
188 return in_8(udbg_uart.mmio_base + (reg * udbg_uart_stride));
189 }
190
191 static void udbg_uart_out_mmio(unsigned int reg, u8 data)
192 {
193 out_8(udbg_uart.mmio_base + (reg * udbg_uart_stride), data);
194 }
195
196
197 void __init udbg_uart_init_mmio(void __iomem *addr, unsigned int stride)
198 {
199 if (!addr)
200 return;
201 udbg_uart.mmio_base = addr;
202 udbg_uart_stride = stride;
203 udbg_uart_in = udbg_uart_in_mmio;
204 udbg_uart_out = udbg_uart_out_mmio;
205 udbg_use_uart();
206 }
207
208 #ifdef CONFIG_PPC_MAPLE
209
210 #define UDBG_UART_MAPLE_ADDR ((void __iomem *)0xf40003f8)
211
212 static u8 udbg_uart_in_maple(unsigned int reg)
213 {
214 return real_readb(UDBG_UART_MAPLE_ADDR + reg);
215 }
216
217 static void udbg_uart_out_maple(unsigned int reg, u8 val)
218 {
219 real_writeb(val, UDBG_UART_MAPLE_ADDR + reg);
220 }
221
222 void __init udbg_init_maple_realmode(void)
223 {
224 udbg_uart_in = udbg_uart_in_maple;
225 udbg_uart_out = udbg_uart_out_maple;
226 udbg_use_uart();
227 }
228
229 #endif /* CONFIG_PPC_MAPLE */
230
231 #ifdef CONFIG_PPC_PASEMI
232
233 #define UDBG_UART_PAS_ADDR ((void __iomem *)0xfcff03f8UL)
234
235 static u8 udbg_uart_in_pas(unsigned int reg)
236 {
237 return real_205_readb(UDBG_UART_PAS_ADDR + reg);
238 }
239
240 static void udbg_uart_out_pas(unsigned int reg, u8 val)
241 {
242 real_205_writeb(val, UDBG_UART_PAS_ADDR + reg);
243 }
244
245 void __init udbg_init_pas_realmode(void)
246 {
247 udbg_uart_in = udbg_uart_in_pas;
248 udbg_uart_out = udbg_uart_out_pas;
249 udbg_use_uart();
250 }
251
252 #endif /* CONFIG_PPC_PASEMI */
253
254 #ifdef CONFIG_PPC_EARLY_DEBUG_44x
255
256 #include <platforms/44x/44x.h>
257
258 static u8 udbg_uart_in_44x_as1(unsigned int reg)
259 {
260 return as1_readb((void __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR + reg);
261 }
262
263 static void udbg_uart_out_44x_as1(unsigned int reg, u8 val)
264 {
265 as1_writeb(val, (void __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR + reg);
266 }
267
268 void __init udbg_init_44x_as1(void)
269 {
270 udbg_uart_in = udbg_uart_in_44x_as1;
271 udbg_uart_out = udbg_uart_out_44x_as1;
272 udbg_use_uart();
273 }
274
275 #endif /* CONFIG_PPC_EARLY_DEBUG_44x */
276
277 #ifdef CONFIG_PPC_EARLY_DEBUG_16550
278
279 static void __iomem *udbg_uart_early_addr;
280
281 void __init udbg_init_debug_16550(void)
282 {
283 udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000);
284 udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE);
285 }
286
287 static int __init udbg_init_debug_16550_ioremap(void)
288 {
289 void __iomem *addr;
290
291 if (!udbg_uart_early_addr)
292 return 0;
293
294 addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000);
295 if (WARN_ON(!addr))
296 return -ENOMEM;
297
298 udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE);
299 early_iounmap(udbg_uart_early_addr, 0x1000);
300 udbg_uart_early_addr = NULL;
301
302 return 0;
303 }
304
305 early_initcall(udbg_init_debug_16550_ioremap);
306
307 #endif /* CONFIG_PPC_EARLY_DEBUG_16550 */
308
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